CNC machining masters often encounter abnormalities in the accuracy of workpiece machining during work, but they do not know where the problem is, which not only causes unnecessary losses, but also greatly affects the processing of subsequent work, increasing the time cost. . Faced with such confusion, let's analyze the reasons for the abnormal processing accuracy.
First, the formation of processing accuracy is the cause of abnormal problems
The reason for the abnormal processing accuracy is often concealed, the diagnosis is difficult, and the troubleshooting is difficult. It is usually caused by the following five main reasons: the zero offset of the machine axes is abnormal; the machine feed unit is changed or changed; the motor Abnormal operation, that is, electrical and control parts are abnormal; axial reverse gap is abnormal; mechanical problems, such as lead screws, bearings, couplings and other components. In addition, the selection of tools, the preparation of machining procedures and human factors may also lead to abnormal machining accuracy.
Second, the CNC machine tool diagnosis criteria
1. External external interior
CNC machine tools are mechanical, hydraulic, and electrical machines, so the onset of the disease will be reflected by these three. The repair personnel should first check from the outside to the inside one by one, try to prevent the unsealing and unpacking as much as possible, otherwise it will expand the fault and make the machine lose precision and reduce the function.
2. First mechanical and electrical
In general, mechanical problems are easier to detect, and the diagnosis of CNC systems is more difficult. Before the fault is repaired, it is necessary to first check the mechanical problems in advance, which can often achieve twice the result with half the effort.
3. After quietly moving
Firstly, after the machine is powered off, the machine can be energized by understanding, investigating, testing, and analyzing the non-destructive problem. Under the operating conditions, conduct dynamic investigation, inspection and testing to find faults. . For destructive problems, the machine must be powered off before the risk can be removed.
4. Simple and messy first
When a variety of problems are intertwined and obscured, when it is impossible to start, it is necessary to deal with simple problems and post-processing difficult problems. Often, after a simple problem is dealt with, the difficult problem will be solved.
Third, the CNC machine tool diagnosis method
1. Intuitive method: (Wang Wen asked) Ask - the machine tool's fault phenomenon, processing status, etc.; see - CRT alarm information, alarm indicator, capacitor and other components deformation smoke and burn, protector trip, etc.; listen - abnormal movement; - Electrical components burnt and other odors; touch-oscillation, heat, poor contact, etc.
2. Parameter viewing method: The parameters are usually stored in RAM. Sometimes the battery voltage is insufficient. If the system is not energized or externally interfered for a long time, the parameters will be lost or disordered. The relevant parameters should be viewed and corrected according to the fault characteristics.
3. Isolation method: Some problems are difficult to distinguish between the numerical control part and the servo system or mechanical part. The isolation method is often used.
4. The same type of adjustment method replaces the template that is suspected of being faulty with the same standby board, or exchanges the same template or unit.
5. The utility program test method writes some small programs for the G, M, S, T, and the full instructions of the function. When these problems are diagnosed when the diagnosis is diagnosed, the missing function can be discriminated.